Lens grinding and polishing machine



y 23, 1939- E. M. LONG 2,159,620

LENS GRINDING AND POLISHING MACHINE I Filed July 26, 1937 :5Sheets-Sheet 1 45' 27 2.9 /3 ,2 4 2a 30 INVENTUR May 23, 1939. E, M NG2,159,620

LENS GRINDING AND POLISHING MACHINE Filed July 26, 1937 3 Sheets-Sheet 2f 2 J 37 39 38 K g 6' l I 42 5 f -34- 4 r j 2' )2 .54; I 32 32 6 60 E f,Em

J 2 2a m 29 0 m4- 65 May 23, 1939. E M. LONG 2,159,620

LENS GRINDING AND POLISHING MACHINE Filed July 26, 1957 3 Sheets-Sheet 3Patented May 23, 1939 LENS GRINDING AND POLISHING MACHINE Eli MaynardLong, Geneva, N. Y., aaslgnor to Sharon Optical Company, Inc., Geneva,N. Y., a corporation of New York Application July 26, 1937, Serial No.155,8 86

12 Claims. (Cl. 51-160) This invention relates to improvements. in alens grinding and polishing machine.

The invention-pertains more particularly to a machine for grinding andpolishing the surfaces of toric lenses and is an improvement upon amachine of the type forming the subject-matter of my Patent r'ifc.1,709,943, issued April 23; 1929.

In the machine of'that patent, the movable element (specifically thelens holder), of a grinding 0 and polishing couple consisting of a lensholder and a lap, is actuated by the combined action of tworeciprocativemovements operating indirections at substantially right angles to eachother,

one reciprocative movement operating substant'i ally parallel with thebase-axis of the lens (usu ally called the lengthwise stroke), and theother reciprocative movement operating substantially parallel with thecylinder axis of the lens being ground (usually called the crossstroke); and a continuous variation or break-up (so-called thirdmovement) is introduced into the latter one only of the'reciprocativemovements, so that I the resultant path of movement of the movableelement of the grinding and polishing couple is a series of curvilinearstrokes, and said movable element goes through a comparatively largenumber of strokes before completing a cycle of operation and repeatingits pattern of movement.

The efllcacy of a machine of the above mentioned type is inherentlylimited to a certain extent for the following reasons. In the firstplace, each stroke must be relatively short in length, owing to thelimited area of the surface of the grinding lap engaged by the lenswhich necessarily limits the length of the stroke of each of the tworeciprocative movements. Secondly, the movable element, which is thelens holder in the machine of my patent,- must move through a differentpath on each successive stroke, and the change of path must besufllciently great to prevent any minute inaccuracies occurring in thesurface of the lap being reproduced on the lens. In other words, thelens must not be moved back and forth across the lap a large number oftimes 46 along substantially the sameline, or else a defective orinaccurate portion of the grinding surface of the lap will produce azone of aberration in the lens surface. If, on the other hand, thechange in the path of movement of the lens be- I0 tween successivestrokes is made too great, the

affected thereby. As a result of these inherent limitationsmachines ofthis type, including the machine shown in my above mentioned patent,

will produce only a relatively low percentage of firstquality lenses.

The main object oi'this invention is to produce an improved lensgrinding and polishing machine wherein the relative movement of the lensand the grinding lap is produced by two reciprocative movementsoperating substantially normal to each other with means associated withboth of said reciprocatlve movements and coacting therewith to break-upor vary the same, thereby producing a maximum change between successivepaths of travel of the lens with respect to the 15 grinding lap, whileat the same time greatly increasing the duration ofv each cycle ofoperation, so that a lens will not be moved twice through the same pathduring the time ordinarily required to grind or polish a surfacethereof. 20

Another object of this invention is to provide simple and efficientmeans, cooperating with the reciprocative movement operating in adirection substantially parallel with the base axis of the lens, orlengthwise stroke, for producing a fourth 26 movement by which avariation will be introduced into said lengthwise stroke, whereby avariation in the point of reversal of the movable element of thegrinding and polishing couple from the normal position of reversal ofmovement there- 30 of, resulting from the combined variablereciprocative movements, is attained during the progressive grinding andpolishing of a lens surface for the purpose of preventing, to a greaterextent than heretofore, the formation of aberrations, 35 waves anddistortions in the surface of the lens incidental to the reversalof themovable element at one and the same point.

A more specific object of the invention is to provide means whereby theextent of the length.- 40 wise stroke of the movable element of thegrinding and polishing couple, produced by that reciprocative movementoperating substantially parallel with the base axis of the lens incombination with the fourth movement, may be quickly and easily variedfor lenses of different curvatures and types.

A further object of the invention resides in providing a novel means forproducing a break-up in the stroke which may be applied to either orboth of. the reciprocative movements.

In other words, I'have endeavored to produce a slow continuous changein'the length of the relative movement of a lens and the grinding andpolishingsurface throughout successive strokes of the cycle of operationover an extended or indeflniteperiod, and thus eliminatethe formation oflines or waves in the lens surface which may cause a zone of aberration.

Other objects and advantages relative to the form and operation of theparts of the machine will more fully appear from the followingdescription taken in connection with the accompanying drawings, inwhich:

Figure 1 is a top plan, partly in section, of a lens grinding andpolishing machine embodying certain features of this invention, with thecover removed to show the interior parts.

Figure 2 is a vertical transverse sectional view taken on line 2-4,Figure 1, showing the cover in place and the upper portion ofthe meansfor producing and maintaining pressure upon the lens carrier arms brokenaway.

Figure 3 is a detail vertical longitudinal sectional view, through thelower portion of the machine, taken substantially in the plane of theline 8-3, Figure 1.

Figure 4 is an enlarged detail horizontal sectional view takensubstantially in the plane of the line 4-4, Figure 3, and illustratingmy novel mechanism for producing a break-up in the stroke used as afourth movement mechanism, that is to say, applied to the drive meansfor producing reciprocative movementof a lens carrier element in adirection substantially parallel with the base axis of the lens.

Figure 5 is an enlarged detail sectional view taken on line 5--5,Figure"4.

Figure 6 is a detail horizontal sectional view, partly in elevation,of-a modiflcation in which my novel break-up mechanism is connected tothe inner end of the main drive shaft, and is used in the place of thethird movement mecha nism shown connected with said shaft in Figures 1,2 and 3, that is to say, for effecting a slow continuous change in thenormal point of reversal of the movable element of the grinding andpolishing couple in a direction substantially parallel with the cylinderaxis of the lens.

Figure 7 15a detail sectional view taken on line 'I-I, Figure 6.

view taken in producing said movement under certain predeterminedadjustments.

Figure 14 is a diagrammatic view illustrating the action of the drivemechanism shown in Figure 6 for producing the cross stroke or movementof the lens supporting element over the grinding face in directionssubstantially parallel with the cylinder axis of the lens under certainpredetermined adjustments.

Figure 15 is a diagrammatic view illustrating succeeding strokes of thelens over the grinding surface of the lap, as produced by my novelmechanism when set in the position indicated in Figures 11 and 12.

Figure 16 is a diagrammatic view illustrating succeeding strokes of thelens over the grinding surface of the lap as produced by the motionbreak-up mechanism shown connected to the main drive shaft in Figures 1,2 and 3.

The machine, as illustrated in the drawings, has the greater portionthereof of usual construction and operation, being similar to that shownin my above mentioned Patent No. 1,709,- 943. The machine is shown asbeing provided with a casing I which carries a pair of lens surfacegrinding and polishing couples. Each couple comprises a lap supportingelement 3 fixedly secured to the front side of the casing vI, and a lensactuating or pressure arm 4 which extends from the interior of thecasing l outwardly through a slot 5 provided in the front wall of thecasing to a position over and beyond the corresponding lap supportingelement 8.

I A main drive shaft 8 is journaled in suitable bearings 1 and Iprovided in the casing I to rotate about a horizontal axis. The shaft isdriven from a pulley 8 mounted thereon exteriorly of the case, saidpulley being adapted to be operated by a belt from any suitable sourceof power,- not shown.

As illustrated in Figures 1, 2 and 3 of the drawings, the inner end ofshaft 8 is provided with an eccentric crank pin in adapted'to' rotatebodily about the axis of the shaft. A connecting rod or pitman H isrotatably mounted at one end upon the crank pin l0, while-the lower endof the connecting rod is provided with a stud II which extends laterallytherefrom in a horizontal plane substantially parallel with the axis ofthe pin It).

An eccentric l8, journaled upon the stud I2, is provided with a wormgear l4 at one end thereof which is in meshing engagement with a worm l5secured to the lower end of a vertically disposed shaft II; which, inturn, is 'journaled in suitable bearings I! and I! provided on theconnecting rod Ii. The shaft l6 has secured to the upper end thereof aworm gear 28 which is in meshing engagement with a worm 2| secured tothe outer end of the crank pin III. A yoke member 23 is rotatablymounted upon the eccentric l8 and is adjustably connected to a curvedportion 24 of an arm 25 by a set screw 26. The arm 25 is secured at oneend, by a set screw 21, to the central portion of a rock frame 28 whichis rotatably connected, by pivot pins 29, to upwardly extending posts orlugs 30 projecting from the bottom of the case I, so that the frame 28rocks about a horizontal axis extending substantially parallel with theaxis of the drive shaft 6 and arranged in a plane at one side of saidshaft. The curved portion 24 of the arm 25 is arranged concentric withand has its center of curvature approximately in the axis of the driveshaft. 8, so that adjustment of the yoke 23 longitudinally of the arm 2ifor varying the degree of rocking movement of the frame 28, will producea minimum amount of tilting movement of the arm 2! and frame 28. It willbe observed that the action of the eccentric l8 and its associated driveshaft l8 and gearing, is to continuously vary the effective length ofthe connecting rod ll connecting the crank pin l0 and the curved arm 25,so that, for a given setting of the adjustable yoke 23, a constantangular rocking movement of the frame 28 will be produced, but theposition of the rocking movement will vary slightly and continuously.

The rock frame 28 carries a pair of upright supports 32 arranged inspaced relation to each other longitudinally of the frame. Each of thesupports 32 is pivotally connected to the frame 28 at opposite sides ofthe axis of rotation of said frame by pivotal pins 33. The supports 32extend upwardly from the pivots 33 and each has the upper end thereofbifurcated to receive'adjacent end portions of a floating frame 34 whichextends in a horizontal plane above the frame 28 and is pivotallyconnected to the supports 32 by pivotal pins 35. It is thus seen that.the floating member 34 constitutes a connecting link between the upperend of the supporting members 32, whereby the supports" will besimultaneously rocked in reverse directions, about the pivots 33, as thefloating frame 34 is reciprocated lengthwise in a manner presentlydescribed.

A pair of reversely arranged substantially L- shaped arms 31 and 38arepivotally mounted at 38 and 40, respectively, upon the floating frame34 to swing about coaxial axes parallel with the axis of the frame 28and drive shaft 5, the L- shaped arms 31 and 38 being movable verticallyindependently of each other for permitting independent operation of thehereinbefore mentioned lens carrying, arms 4 which are pivoted, at 42,to the L-shaped arms 31 and 38, respectively. The pivots 42 of each lensoperating arm 4 are disposed in approximately the horizontal plane of,and nearly coaxial with, the pivots 35, as shown in Figures 2 and 3, sothat arms 4 may swing about parallel axes at substantially right anglesto the axis of the rock frame 28 anddrive shaft 6 to compensate forvarying positions of their respective lens holders 43 when moving acrossthe face of their corresponding laps 44.

The construction and'operation of the .mechanism thus far described issubstantially the same as that shown in my Patent No. 1,709,943, and isadapted more particularly for producing reciprocative movement of thelens supporting arms 4 in directions substantially parallel with theshorter or cylinder axis of the lens. The mechanism which includes thenovel features of this invention, forproducing reciprocative movement ofthe lens supporting arms 4 in directions substantially parallel with thelongitudinal or base axis of the lens, will now be explained.

The main drive shaft 6 is provided with a worm 45 positionedintermediate the bearings 1 and 1. The worm 45 meshes with a worm'gear46 rotatably mounted upon a fixed shaft 41 secured to the casing beneaththe drive shaft by a set screw 48, Figure l. A yoke 50, connected withthe worm gear 46 byarms 5|, is rotatably mounted on shaft 41. The arms5| cause the yoke 50 to rotate in unison with the gear 46 and form anintervening space for receiving a pair of collars 52 which are securedto the shaft .41 to hold the gear 45 and yoke 50 against axial movementwith respect to shaft 41. A crank pin 54 is journaled for angularadjustment in the yoke member 50 at one side of and parallel with thestationary shaft 41. The crank pin 54 is held in different positions ofangular adjustment by means of a clamping screw 55 engaged in adiametrically extending threaded aperture in the crank pin 54 and whichextends outwardly from the crank pin through an elongated slot 55provided in the adjacent portion of the yoke 50 to permit relativerotary adjustment of the screw. Mounted in the threaded aperture in thecrank pin 54 is a friction block 51, positioned at the inner end of thescrew 55, adapted to be brought into frictional contact with theperipheral surface of the wall of the aperture 50' receiving the crankpin 54 for releasably maintaining said crank pin against rotationrelative to the yoke 50.

The crank pin 54 is provided with a reduced eccentric extension 54'which is substantially parallel with the axis of the crank pin.Rotatably mounted upon the extension 54' is an eccentric sleeve 59, uponwhich is rotatably mounted a drive sleeve 58 which, in turn, ispivotally connected, as at 5|, to one end of a pitman 62, having itsother end connected by a universal joint 63 to the floating frame 34(see Figures 3 and 4). The outer end of the eccentric sleeve 55 hasconnected therewith a gear 65 which, in this instance, is of greaterdiameter than the sleeve 58 and coacts with an annular flange 56,provided on the crank pin 54 at the inner end of the extension 54', for'maintaining the drive sleeve 50 against axial displacement. Theeccentric sleeve 58 is maintained against axial displacement, relativeto the extension 54', by a bracket 61 secured to the outer end'portlonof the extension 54', as shown in Figure 4.

Journaled in the bracket 51 is a stub shaft 58 arranged at one side ofthe extension 54' in parallel relation therewith. The shaft 58 extendsoutwardly at both ends beyond the sides of bracket 51 andhas secured toone end thereof a pinion 69 which is in meshing engagement with the gear65. The other end of the shaft 58 has secured thereto a gear which is inmeshing engagement with a pinion 1| rotatably mounted upon a reducedportion 54" of the extension 54 and which is arranged in coaxialrelation with said exten-- sion 54'. To the outer end of the pinion 1|is secured an arm 12. This arm 12 is fixed to the pinion 1|, extendsradially therefrom and is provided with an elongated slot 12 whichslidably receives therein a holding pin 13 secured to the adjacent frontwall of the casing I, as shown in Figure 9. Pin 13 and slot 12 are sorelated to each other that arm 12 may freely move longitudinally as thegear 1| revolves about'the axis of shaft 41.

Thelens or lenses to be ground may be fastened, in any suitable manner,to the underside of the lens holder or block 43 for reciprocativemovement across and upon the upper face of the lap 44, carried by thecorresponding supporting element 3 for grinding and polishing purposes.It will be understood that the outer end portions of lens actuating arms4 may each be moved toward and from the lap'supporting elements 3independently of each other, by any suitable means, to permit theremoval and replacement of the lens holder 43, while the lens carried bythe holder may be yieldingly held in pressure engagement with the lap 44by any suitable means. as by an upright pressure rod and a spring 11,portions of which are shown in Figure 2.

It will now be observed that when the main drive shaft 5 is beingrotated, a lens, carried by one of the arms 4 in pressure engagementwith the corresponding lap 44, will be moved across the grinding surfaceof the lap with a curvilinear movement compounded of two reciprocativemovements operating at right angles to each other and two break-upmovements, each of the latter movements being associated with arespective one of the reciprocative movements.

To explain more explicitly, the rotation of crank pin l8 about the axisof shaft 5 will produce a rocking movement of the frame 28 about thepivots 29. This rocking movement of frame 28 will produce acorresponding reciprocative movement of the upper portion of thesupports 32 and the arms 4 carried thereby in a direction substantiallyparallel with the cylinder axis of the lens mounted on said arms,inasmuch as the axes of pivots 29 extend in a plane substantially normalto the cylinder axis of the lens. At the same time, the rotary movementof eccentric 13, produced by the gear members 2| and 25, shaft and gearmembers l5 and I4, will cause a relatively slow independent movement ofthe yoke 23 and arm 25 in the direction of the length of the connectingrod H, and this independent movement is transmitted to the arm 4 andlens actuated thereby through the frame 25, supports 32, frame 34 andarms 31 and 38, thereby caus-.

Y ing a' continually varying effective length 'of the'connection betweenthe driving shaft 5 and arm- 25 which, in turn, causes a continuallychanging scope and field of action of the. lens holder and lens carriedthereby across the grinding surface of the lap, as indicated in Figure16, in the same manner as shown and described in my Patent No.1,709,943.

In my-novel drive mechanism, the lens actuating'arms 4 and the lensconnected therewith are re'ciprocated longitudinally of the lap 44 bythe rocking of -.frame 34 and supports 32 about the axes of the pivots33 and 35. produced by the crank pin 54 as the same is rotated about theaxis of shaft", through the medium of the drive sleeve 60 and crank arm52. During this rotary movement of the crank pin 54, the length of thelengthwise stroke of the floating frame 34 will be constantly changingdue to a continually varying effective length of the crank armconnection between the axis of shaft 41 and the connecting rod 52. Thiscontinuously varying effective crank arm length-is produced by therotation of eccentric sleeve 59 upon the crank pin extension 54,

shaft 41; the points 54 represent the axis of the crank pin 54 mountedin the yoke 50;.the points 54' represent the axis of the crank pinextension 54'; and'the points 59 represent the axis'of the eccentricsleeve 59;'the two sets of points 54, 54' and 59 in each figure beingrepresented in different positions 180 apart; The full and broken .lines52 represent the connecting rod 52 in its extreme forward andback.positions. Line 34 represents'the frame 34 and lines 32 representthe supports 32. The circle X represents the path of movement of thecrank pin 54 about the axis of-the shaft 41, while the circle ,Yrepresents the path of movement of the axis of the crank pin extension54 about the shaft 41. Circle X indicates the possible path of movementof the axis of-th'e extension 54' during adjustment of said crank pinwithin the yoke 50, while the circle Y represents the path of movementof the axis of the eccentric sleeve 59 about the axis of the crank pinextension 54 during the rotation of the sleeve upon the extension.

It will now be evident that when the crank pin' 54 is adjusted relativeto the yoke 50 to obtain the maximum degree of travel of the crank pinextension 54 about the axis of the shaft 41, as shown in Figures 11 and12, the-lens carrier pin 4' connected with the lens carrier arm 4 willbe moved a maximum distance'over the grinding surface of the lap 44 asthe crank pin 54 revolves about the shaft 41-. I

It will also be obvious that inasmuch as the eccentric sleeve 59 isbeing constantly rotated at a relatively slow rate of speed, thelongitudinal center of the sleeve 55 will be slowly rotated about theaxis of the extension 54', thereby constantly varying the effectivelength of the crank connection between the axis of shaft 41 and theconnecting rod 52, and causing each arm 4 to move through graduallyvarying distances within the limits shown by the full and broken lines 4in Figure 11. In other words, the arm 4 will move between the positionsobtained by the maximum degree of throw produced by the combined actionof the crank pin and eccentric sleeve, as shown in Figure 11, and theminimum degree of throw as shown in Figure '12.

The setting of the crank pin 54 to-obtain the maximum degree of movementof the lens carrier arm 4 is utiiized with a lens having a substantiallyflat surface or one in which the'curve of the surface being ground hasarelatively long radius. When the surface of the lens being ground has arelatively short radius, the crank pin 54 is adjusted in the yoke 55 tobring the axis of the extension 54' thereof into relatively closerelation with the axis of the shaft 41. When the crank pin 54 is thusadjusted to obtain the minimum degree of action produced by the crankpin, as indicated diagrammatically in Figure 13,

the carrier arm 4 will obviously have a much less degree of movementthan with the previously described adjustment of the crank pin.

It'wifl be observed, however, that owing to the driving connectionsbetween thecrank pin extension 54' and the eccentric sleeve 59 and therelatively slow speed of rotation of the eccentric sleeve thus produced,the position of the point of connection between the arm 52 and sleeve 60is continuously but slowly changing with respect to the axis ofextension 54' and t at at every revolution of the eccentric 59 upon heextension bility ofscoring or otherwise injuring the lens as the lens ismoved longitudinally of the base curve. of the lap 44 by any errors orimperfections in the grinding surface of the lap.

The above described action of the crank pin ex- .tension 54' andeccentric sleeve 59, upon the frame 34 andarms 4, is equally truewhen,the crank pin 54 is adjusted to obtain the minimum degree of travelof the lens across the lap 44, as shown in Figure 13, wherein.theminimum and maximum amount of travel of an arm 4, for such adjustment,is indicated at aand b respectively.

In Figures 6, 7, 8 and 10, I have illustrated the use of my novelbreak-up mechanism-for the purpose of producing the break-up movement ofthe cross stroke, that is to say, applied to the means for reciprocatingthe floating frame 34 in directions parallel with the cylinder axis ofthe lens and lap. In this structure, the drive shaft 8 has the crank,pin 10 thereof rotatably supporting the eccentric sleeve 59 and gear55, while the bracket 61 is secured to the outer end of the crank'pinHi. This bracket 8 rotatably carries the shaft 68,

'which-inturnhas the pinion '69 secured to one end anId-thegear' 10securedto the other end thereofflThe pinion 69 is in meshing engagementwiththe gear 55while the gear 10 is'in meshing engagement'with thepinion H which is 'J'ournaled on an extension Ifl'provided on the outerend of the crank'pin ID in coaxial relation therewith.

The pinion II is maintainedgagainst rotation during the rotation of theextension l about the axis of the shaft 6 by a pair of links 80 which'are pivotally connected, as at- 8|, Figure 10, to each other. One ofthe links is pivotally connected,

as at 82, to the rear wall of the casing l,.while the other link isfixedly secured to the pinion H.

Rotatably mounted upon the eccentric sleeve 59 is a connecting rod 84which extends down- 25 the outer end'thereof a yoke 86, similar to the aset screw 81.

through the supports 32 yoke 23 shown in Figure 2. This yoke 06 isprovlded with an aperture extending therethrough substantially normal tothe stud for receiving the curved end portion 24 of the arm 25. The yokeis adjustably secured tothe arm 25 by Inthe construction shown in Figure6,-the effective lengthqoi' ,the crank arm connection between the axesof shaft 6 and connecting rod 84 is constantly changing,- as illustrateddiagrammatically in Figure"14, due to the continuous but relatively slowrotation of the eccentric sleeve 59 upon the crank pin III, as the crankpin l0 revolves about the axis of the shaft 6. This continuous rotation'of eccentric sleeve 59 upon crank pin I0 is caused b y the rotarymovement transmitted to the gear ifi by pinion 69 asex'plainedhereinbefore for the structure shown in Figure 4. This gradual increaseor decreaseln the effective length of the crank arm connectionbetweenthfe axis of shaft 8 and rod84 producesa corresponding variation inthe'length oftlie stroke thereof and the angular extent of th rockingmovement of the frame 28, which n'rent is transmitted raine 34 and arms31 and 38 to the lens actuatingj'arm's 4 and the lens actuated'thereby.V

' In other words; when the stud 85 has been moved to its extreme upposition by the combined action of the eccentric sleeve 59 and the crankl0, through the medium of the connecting rod 84, in which position thehigh point of the eccentric sleeve 59 is directly over the axis of thestud 85, then the point of connection between the arm 25 and yoke 86will assume a position at A, Figure 14, at the upper limit ofv themovement of the stud 85. When the crank pin H) has been moved 180to itslowermost position and the eccentric: sleeve has been rotated so thatthe longitudinal center thereof lies directly below the axis of the Stud85, then the-point of connection between the 'arm 25 and yoke 86 willassume a position at A at theextreme lower position of its movement;These'extreme positions of the 'pointof connection between the yoke 86and the driving connectionsbetween the crank pin l0 and the eccentricsleeve 58 and the relatively slow speed'of rotation of said sleeveproduced by said connection, the effective length of throw of crank pinI0 is continually but slowly changing. At every changing of the lengthof this throw, a corresponding change in the length of the cross strokeof arms 4 is produced even as the length of the lengthwise stroke iscontinually changing when my novel motion break-up mechanism is mountedon crank pin 54 as explained hereinbefore and as illustrated in Figure15. 7

It will now be clear that when my novel breakup mechanism is applied tothe means for recip'rocating the lens longitudinallyof' the grindingsurface of the lap, as shown in Figure 1, the center of eachreciprocative stroke'will be substantially coincident with the minoraxis of the lap as illustrated in Figure 15, wherein line NN representsthe minor axis of the grinding lap and lines M represent succeedingstrokes of a pin 4' lengthwise of the lap. Also. it will be understoodthat when my novel break-up mechanism is applied to the means forproducing the cross stroke, or for moving the lens transversely of thegrinding surface of the lap, as shown in Figure 6, it will likewiseproduce strokes which are of varying. lengths, and wherein the centersof the strokes, as indicated by line NN, Figure 15, extend in a straightline, are substantially coincident with the major axis of the lap.

It therefore follows that the combination of the two circular movementsproduced by my novel break-up mechanism with the two reciprocativemovements will produce a continuous change in the position of the endsof the succeeding strokes of the lens across the grinding surface of thelap due to the continually changing lengths of both the -lengthwise andcross strokes.

If, however, the motion break-up mechanism applied to the cross strokeis substantially the same, as that shown in my Patent No. 1,109,943, andillustrated in Figures 1 and 2 of this applicatiohjthe general directionof movement of the lens across the face of the lap is through a more orless serpentine path, as illustrated in Figure 16L0f the drawingswherein the line O-O represents the major axis of the grinding lap,lines M represent succeeding cross strokes of a pin 4' upon the lap, andline PP represents the center line of each stroke. These differences inthe character of the variations introduced into the lengthwise and crossstrokes Whenmy novel break-up mechanism is applied to the drive pin 54:and the break-up mechanism shown applied to the crank pin 10 in Figures1 and 2. are due to the fact that in the break-u mechanism shown inFigure 4 the rotation of the eccentric sleeve 59 causes a change in theeffective throw of said sleeve and has the effect of continuallyincreasing or decreasing the eccentricity of the crank pin 54 with aresultant increase or decrease in the length of the stroke produced bythe combined action of the eccentric sleeve 59 and crank pin extension54'. illustrated by Figure 15. In the break-up mechanism connected withcrank pin Iii, Figures 1 and 2. the rotation of the eccentric l3produced by the gear members 2| and 22, shaft l6 and gear members !5 andM. has the effect of continuously increasing or decreasing the lengthtofthe connecting rod ii, while main taining a substantially uniform lengthof stroke because the throw of eccentric I0 remains constant. Acorresponding change is thus produced in the position but not in thelength of the cross stroke of arms 4, as illustrated by Figure 16.

It will be seen from the foregoing that the resultant effect produced bymy novel break-up mechanism, when used in connection with the lengthwisestroke in combination with the breakup mechanism shown in Figures 1 and2, connected with the cross stroke, upon each of the arms 4 and the lensholder actuated thereby will be to reverse their motion at constantlychanging points during succeeding strokes while the general field ofoperation thereof is maintained substantially constant. This is due tothe lengths of the longitudinal strokes being constantly varied, asshown in Figure 15, while the length of the cross strokes are maintainedsubstantially equal, but the general field of operation thereof isconstantly changing as indicated in Figure 16. In other words, whethermy novel break-up mechanism is used in connection with the cross stroke,as shown in Figure 6, or the break-up mechanism, shown in Figures 1 and2, is associated with the cross stroke, the combination of either ofthese movements with the break-up mechanism, shown connected with thelengthwise stroke. when combined with the two reciprocative movements,will produce a continuous change in the position of reversal of movementof the lens across .the grinding surface of the lap during eachsucceeding stroke without materially decreasing the length of the strokeproduced by the combined action of the two reciprocative movements. At

the same time the cycle of operation or the period drawings, each cycleof operation actually con.

tinues without repeating any stroke for several hours of operation,while the operation of the machine of one grinding or polishingoperation seldom exceeds twenty minutes. n the other hand, in themachine of my Patent l lo ,7 9, 4 in which only the variation producedby the coaction of gears l4, I5, 20 and 2| and eccentric sleeve IS .inconnection with the cross reciprocating movement is employed, the cycleof operation repeats about once every minute or in about every 450revolutions of the drive shaft 6. Furthermore my novel break-upmechanism is applicable for introducing a variation into either thecross stroke or the lengthwise stroke or both, but'this is not true ofthe break-up mechanism of my said patent which is applicable onlyin'connection with the cross stroke as illustratedtherein. It is thusevident that the efficiency of the machine of the present invention ismaterially increased over that of said patent and a resultant increasein the percentage of first quality lenses, as that term is understood inthe optical industry, is obtained with the machine of this application.

Although the construction and operation of the novel features of themechanism above described are particularly simple, practical andeflicient, I do not wish'to be limited thereto as it is evident thatvarious changes may be made in the detail construction without departingfrom the spirit of the invention as set forth in the appended claims.

I claim:

1. In a lens grinding and polishing machine having a lens grindingelement and a lens holding element mounted in cooperative relation witheach other, in combination, operating mechanism for producing relativemovement of said elements to effect grinding of the lens carried by theholding element comprising two operating members, two drive means, onefor each operating member, means operatively connecting said drive meanswith the operating members for producing reciprocative movement of eachoperating' member in directions substantially normal to thereciprocative movement of the other operating member, each of saidconnecting means including a break-up mechanism adapted to causevariations in the reciprocative movement produced by said connectingmeans to effect operation of the operating member through continuouslychanging paths, and means for simultaneously operating said drive means.

2. A lens grinding and polishing machine as in claim 1 wherein at leastone of said break-up mechanisms is of such'a character that the actionproduced thereby is to constantly vary the length of eachsucceedingreciprocative stroke of the operating member operated thereby.

each other, in combination, operating mechanism for producing relativemovement of said elements to effect-grinding of the lens carried by theholding element comprising two operating members, two drive means, onefor each operatng member, means operatively connecting said alive meanswith the operating members for producing reciprocative movement of eachoperating member in directions substantially normal to the reciprocativemovement of the other operating member through continuously changingpaths, and means for simultaneously operating said drive means, one ofsaid connecting means including a mechanism for constantly varying thelength of each succeeding reciprocative stroke of the memberoperatedthereby while maintaining the center of said strokessubstantially constant with respect to a plane extending therethroughnormal to said strokes and the other connecting means includingmechanism for constantly varying the position of the center of eachsucceeding stroke of the member actuated thereby lengthwise of thestrokes while maintaining said strokes of the member at a substantiallyuniform length.

5. A lens grinding and polishing machine as in claim 4 having meansadjustable at will connected with said operating mechanism for varyingthe amount of movement of each operating member.

6. In a lens grinding and polishing machine having a lens grindingelement, a lens holding element, and operating means comprisingrelatively movable members for one of said elements, in combination, arotary drive shaft, mechanism connected with certain of the movablemembers of the operating means and actuated by said shaft for imparting"a reciprocating movement to the element actuatedby said operating meansin a predetermineddirection with respect to the other element, se aratemechanism connected with the other said movable members and actuated bythe driveshaft for imparting a reciprocating movement to said elementactuated by the operating means in a direction substantially normal tothe first mentioned direction of movement thereof with respect tothe-other element, each of said mechanisms including a break-up meansactuated thereby for automatically varyingthe normal path of movement ofthe element actuated by the operating means in each of saidreciprocating directions during each revolution of the drive shaft.

' 7. A device as in claim 6 wherein one of said drive mechanismsincludes means adjustable at will for varying the amount of movement ofsaid members of the operating means and of said element carried thereby.

.8. In a lens grinding and polishing machine having a lens grindingelement, a lens holding element and'a movable driving means for one ofsaid elements, in combination, means for operating the driving meansincluding a drive member mounted to rotate about a fixed axis, a crankmember connected with the drive member in eccentric relation therewithto revolve about said iixed axis, an'eccentric member rotatably mounted.on the crank member, means rotatably connected to the/eccentricmemberfor actuating the driving means to and no for producingreciprocation 01 said elenient' actuated thereby in a predetermineddirection with respect to the other element, Wei-Gilliam bythe.revolving motion of the crank member forrotating the eccentric memberrelative 'tosaid crank member for varying 4 said path ofreciprocating'movement of said element including aarain ot gears mountedon the crank member to revolve therewith about said fixed axis, eachgear of said train being adapted to rotate relative'tos'aid crankmember, and means connected one; of the gears of said train for holdingthe'same stationary with respect toits axis 01' rotation. I

9. A device as 'in claim 8 having means for adjusting the crank membertoward and from said fixed axis to alter the path of travel thereofabout said fixed axis.

10. In a machine for grinding lenses or the like having a grindingelement and a work supporting element, means connected with one of saidelements for producing movement thereof relative to the other elementcomprising an eccentric member having an axis of rotation, operatingmeans rotatably supporting the eccentric member adapted to revolve saidmember about a second axis arranged in spaced substantially parallelrelation with said axis of rotation, means for rotating the eccentricmember comprising a drive ele-- ment having an axis of rotation, meansrotatably supporting. said drive element in coaxial relation with theeccentric member and adapted to revolve said drive element about saidsecond axis in unison with the eccentric member, holding means conncctedwith the drive element having movement therewith during the revolutionthereof about said second axis and adapted to maintain said elementagainst rotation about the axis of rotation, and separate rotatablemeans movable in unison with the operating means about said second axisand actuated by the drive element for producing rotation of saideccentric member about said axis of rotation thereof.

11. A machine of the class described in claim 10, wherein the operatingmeans includes relatively movable members adjustable with respect toeach other for producing relative movement of the axis of rotation ofthe eccentric member and said second axis toward and from each other,and means for releasablysecuring said members in the adjusted position.

12. In a lens grinding machine having a grinding element and a workholding element mounted in cooperative relation with each other andwherein an actuating arm connected with at least one of said elements isoperated by means comprising a pair of reciprocative members and driveelements operatively connected with said reciprocative members andmounted to revolve about fixed axes for producing relative movement ofthe work carried by the holding element and said grinding element ingrinding engagement with each other by the combined action of tworeciprocative movements operating in directions substantially normal toeach other, in combination, separate oper-- ating means including a..pair of eccentric sleeves and drive members therefor actuated by therevolving motions of the drive elements, said sleeves and drive membersbeing so constructed and arranged that two reciprocative break-upmotions are produced by two circular motions and said break-up motionscombine with said reciprocative ELT MAYNARD LONG.

